1// SPDX-License-Identifier: GPL-2.0
 2
 3//! The `kernel` crate.
 4//!
 5//! This crate contains the kernel APIs that have been ported or wrapped for
 6//! usage by Rust code in the kernel and is shared by all of them.
 7//!
 8//! In other words, all the rest of the Rust code in the kernel (e.g. kernel
 9//! modules written in Rust) depends on [`core`], [`alloc`] and this crate.
10//!
11//! If you need a kernel C API that is not ported or wrapped yet here, then
12//! do so first instead of bypassing this crate.
13
14#![no_std]
15#![feature(allocator_api)]
16#![feature(core_ffi_c)]
17
18// Ensure conditional compilation based on the kernel configuration works;
19// otherwise we may silently break things like initcall handling.
20#[cfg(not(CONFIG_RUST))]
21compile_error!("Missing kernel configuration for conditional compilation");
22
23#[cfg(not(test))]
24#[cfg(not(testlib))]
25mod allocator;
26mod build_assert;
27pub mod error;
28pub mod prelude;
29pub mod print;
30mod static_assert;
31#[doc(hidden)]
32pub mod std_vendor;
33pub mod str;
34pub mod types;
35
36#[doc(hidden)]
37pub use bindings;
38pub use macros;
39
40#[doc(hidden)]
41pub use build_error::build_error;
42
43/// Prefix to appear before log messages printed from within the `kernel` crate.
44const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
45
46/// The top level entrypoint to implementing a kernel module.
47///
48/// For any teardown or cleanup operations, your type may implement [`Drop`].
49pub trait Module: Sized + Sync {
50    /// Called at module initialization time.
51    ///
52    /// Use this method to perform whatever setup or registration your module
53    /// should do.
54    ///
55    /// Equivalent to the `module_init` macro in the C API.
56    fn init(module: &'static ThisModule) -> error::Result<Self>;
57}
58
59/// Equivalent to `THIS_MODULE` in the C API.
60///
61/// C header: `include/linux/export.h`
62pub struct ThisModule(*mut bindings::module);
63
64// SAFETY: `THIS_MODULE` may be used from all threads within a module.
65unsafe impl Sync for ThisModule {}
66
67impl ThisModule {
68    /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
69    ///
70    /// # Safety
71    ///
72    /// The pointer must be equal to the right `THIS_MODULE`.
73    pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
74        ThisModule(ptr)
75    }
76}
77
78#[cfg(not(any(testlib, test)))]
79#[panic_handler]
80fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
81    pr_emerg!("{}\n", info);
82    // SAFETY: FFI call.
83    unsafe { bindings::BUG() };
84    // Bindgen currently does not recognize `__noreturn` so `BUG` returns `()`
85    // instead of `!`. See <https://github.com/rust-lang/rust-bindgen/issues/2094>.
86    loop {}
87}